Process and apparatus for superheating steam



Nov. 17, 1931. c. KARRlcK 1,832,219

4 'PROCESS ANDAPPARATUS FOR SUPERHEATING ISTEAM Filed July 5, 1928 Fig-3 Fig-sz ATTORNEYS arid cheapness. y my Patented yNov. 17, 1931 i LEWIS c. xumcx,

F SALT LAKE CITY, UTAH PROCESS AND APPARATUS FORr SUPERHEATING: STEAM Application filed July 5,

This invention relates to a process. and aparatus for superheating steam to high te peratures in contact with certain reacting rea a s o which the the chemical reactions which take higher temperatures, valuable b a result of these y-products the superheater delivers more heat at th than would be p ossible if no reagents were used; other advantages of my invention Iare also described 1n this application. v

There are manyY processes in 'which high means were provided for heating the steam above 900 F. and particularly above The distillation of carbonaceous mal shale and coals or woo internal heating wit and these same materials be completely gasified in lump or pul- 1250 F. alloys and designs of equipment have been attempted for heating Asteam to temperatures above 900 F. wit only'lixrted success due to the diiiculty of combining in the prod uct the elements o strength, resistance to oxidation, permanence, invention steel, and alloys of iron and chro-A ich are readily fabricated may be temperatures considerably higher than has heretofore proved practicable, and the latter twomateria s may be used successfully above 1250o F. and as much higher as the strength of the materials and service conditions permit. I find that if a such as is produced by the bed in my application, Serial No. 69,300, or other similar coke is introduced in pulverized form into the superheater with the steam, bination with the steam takes place rapi at temperatures as low as 1250 F. and much calorized steel,

- temperature steam could be used if suitable p hby 192e. serial No. 290,352.

be rapidly reacted upon to At the lowest temperatures water-gas reaction yields a large amount of carbon dioxide which mayl oxodize the iron of the superheater within certain temperature ranges'unless special precautions are applied to oppose it. he rate. of oxidation of iron by steam in the presence of reactive carbon is almost negligible below 12.50 F. but, if desired, calorized steel or an 55 alloy of iron and chromium ma be used in the hottest portions fthe tu es. Above 1250o F. the carbon dioxide formed maybe largely reduced to carbon monoxide if a surlus of carbon is use and thereby oxidation 5b from this source is eliminated. At still higher temperatures both the steam and carbon dioxide are readily reduced to hydrogen and carbon monoxide in any proportion desire proper control of temperatures and the proportioning of the carbon and steam, an therefore no serious oxidation takes place since, in all cases,1 use a sufficient quantity of coke to cause a neutral or only slightly oxidizing atmosphere in the tubes.

In a heat-exchanger, a recuperator or, as in this invention which is a steam superheater wherein heat is caused to flow from hot combustion gases through a metal wall to steam or other Ifluid, the temperature of the metal wall iapproaches nearest to .that of the contacting gaseous medium which receives or delivers its heat most readily. If the .heat capacities of the fluid media are equal then the .metal temperature ap roaches that of vthe medium that moves the fastest along the metal surface. These conditions are applic m this invention so as to obtain the greatest rate of heat transfer, the highest temperature of the medium receiving hea and lowest metal temperature for any given temperature and velocity of movement of the combustion ases surrounding the heat exchan er.

that steam super ca ted 1 have f various temperatures is very useful m dis- 00 of the coke may form water gas. of formation the ound steam to 19500 tilling carbonaceous substance ly dir ect contacting with the material un ergoing destructive distillation. Also, hot water-gas is dioxide to form water-gas or producer gas, and l have shown by this invention that ace rapidly when at lower temperathan are required in present day proucers and water-gas generators using high temperature cokes. I have found that much o e carbon dioxide contained in blue g reduced to carbon monoxide by n carrying out the features of clean steam such as engine exhaust steam or steam produced from a waste heat reculocities counterflow to hot combustion ases which flow rapidly across the tubes. y properregulation of steam e the gases surroundthaii 22000 F. at the was added `cal equilibrium may be transmitted through heating water-gas ture at which th place.

steam2 or both, are completely consumed the f resulting be raised to any sired temperature before leaving the device.

ere is a surplus of steam, the resulting gas will be -hifgh 1n carbon dioxide but if there is an excess o coke, the resulting gas will contain more carbon mmoxide and be of higher s was less due to th coke and steam t fuel value and, obviously, is a highly reducing atmosphere.

By this process tial in securing long life and economical oph superheats to is process of coke steam ratio varied to govern the exit temperature of the fluids and the temperature of he metal walls.

y my process of superheating steam in contact with carbonaceous materials it is posmore pounds of the conditions imposed are he oxygen of the'reacting steam.

temperature. It convert as much as practicable of th to water gas of the latter form because of its greater fuel value,

t e greater economy steam.

By this process I an generated water-gas v and coke at pressures lump coal carbonizer in which heats of the fluids distilled the coal and t ence passed into a heat exchanger and condenser leaving the cold dry gas under preshave' superheated steam gears 17 from it contacts bedded in insulating sures amply high to transmit it long distances through pipes.

also be used in a heat exchanger while under pressure to generate another suply of steam at lower pressure for use in another similar superheater, or to superheat steam instead of using combustion gases as a source of heat. Any number of these units or combinations may be used in series as required to consume the coal or coke dust at a power plant, gas works, or coal-treating plant. O

The invention will be understood from the description in connection with the accomanving drawings in which an illustrative embodiment of the device is ing out the invention. Fig. 1 tion through an illustrative be used in carrying out the invention; Fig. is a section along one of the details on an enlarged scale partly broken away; an ig. 3 is a section along the line 3-3 of Fig. 21. ln the drawings reference character 1 indicates a heater or furnace, preferably circular in cross section that is provi ed with an inside cylindrical portion-or core 2 to provide an annular space hown for carryis a vertical secdevice that may Sfwhich is of smaller cross section at the top so as to maintain high velocity of combustion gases. The lower po ion o the annular space contains checkerwork"` 4 of refractory material and burners 5 are pro- 1 through the burners 5 rise vided at the lower portion of the furnace to project fuel into the annular space where with the checkerwork 4 and undergoes combustion. The burners may be gas burners that are fed from a gas manifold 6 do not'limi my invention to this manner o heating and in some cases I would prefer to heat electrically during ott` peak periods an the tube woul, become the electrical resister being imbedded in a heat insulating material, line being attached to the coil 7 as and 7 The coil 7 may be immaterial such as low temperature coke having reducing properties, if desired, and be prevented Jrom grounding b using insulating gaskets in the connections with the pipes leading to and om the gasifier. c c

A tube coil 7 of large radius and with no sharp turns is installed in the annular space 3 and the convolutions thereoi` are space an supported by means of the vertically extending supports A chimney or outlet 9 is rovided at the top of the furnace. j

A coal hopper 10 for pulverized coal or coke or other carbonaceous material leads through the valved outlet 11 to a magazine 12 troni'which a valved outlet 13 leads to the bin 14. A stirrer shaft 15 extends through the magazine 12 and bin 14`and is provide with blades or arms 16 Jfor stirring the material. The shaft is driven by means ot the any convenient source oi'powto a similar jacket 2 bers.

f with the same valve 13 is closed. The valve 11 is condensing er. A screw 18 is provided at the lower end of the haft 15 to assist in preventing iloo. -ing orirregular iow of the aerated or pulverized material from the bin 14 into the coal feeder.

A steam jacket 19 surrounds the magazine 12 and a steam pipe 20 leads steam to this jacket. A pipe 21 leads Jfrom the jacket 19 22 that surroun s he bin 14 and this jacket is connected to the jacket 23 that surrounds the housing 24 of a coal feeder.' \A valved pipe 25 leads from the jacket 23 into the housing 24 and'serves to maintain a jacket pressure a in the superheater and insures a inside the magazine and bin higher than th temperature of the steam at superheater pressure, thus obviating any possibility of steam condensing in the two cham- The mechanical screw feeder 26 is located inside of the conveyor housing 24 and is driven from any convenient source of power by means of the gears 27. c The housing 24 of the coa-l feeder leads to the inlet end of the coil 7 and this coil is'provided with a twisted Y metal, so as to cause a large portion ofthe solid particles to be thrown out against the inside walls o the pipe 7 and be carried al to absorb heat therefrom.

` follows: The hot prod- The operation is as tuel introduced ucts of combustion i space 3 and heat the coil 7 and then pass out through the outlet 9. A batch of pulverized carbonaceous material is passed from the pper 10 into the magazine 12 while the then closed and .the valve 13,0pened, whereupon the puld verized carbonaceous material passes into the 14 enter the coil 7 After magazine` l2 is empty the valve 13 is closed and a new charge is introduced into the magazine and the operations repeated as described. rlhe stirrer arms 16 keep the material agitated so that it will become quic ly heated from contacting with the hot walls o and will maintain a iiuidized condition. The screw conveyor 26 Jreeds the material into the tube 7 at the vdesired rate and at the saine that has entered through the pipe 2() and passed through the jackets 19, 22 an dered naceous material and any water from condensation of steam into the coil 7 where the water is evaporated and the mixture is heated during which the desired reactions are caused to take place. The superheatd steam and other roducts pass out thrqugli the exit en 9 of the coil 7 and may be cleaned and separated into its constituents in any of the convenient and `well known ways, or the sensible heat of the products can be used for the different urposes described herein. I have used steam velocities above 600 eet per second.

carbothrough the magazine 12 and bin 14 and the he upper part y I may use any other reacting ingredient be,- sides coke. I claim: l y 1. The process of superheating steam within metal tubes to high temperatures in contact with solid car 2 which steam and car chemically substantially instantaneously to form water gas, the velocity being such that a scouring action by said solid carbonaceous materials maintains clean inner surfaces of Said tubes.

as 2. The

steam under pressure and at high velocity and heating tlie mixture above d effecting a chemical combination of said solid carbonaceous material with zones and removing the resulting products at the point of highest velocity of How.

The process of 63 contact with steam under pressure into a tube, heating the tube to increase the temperature of the cons tents above 1250 F.,

passing tu contents of said tube at substantially their highest attained tem erature.

5. The process ofpsuperheating steam in contact with solid carbonaceous material w ich comprises introducing the sohd carmaterial introduced per unit of time, and causing tlie tube contents to rotate at increasing velocity while Eassing through form together with steam un er pressure intoa tube, heating the tube from th and regulating the amount o steam and carbonaceous material introd per unit of time.

he process of contact with tents of In a device for superheating steam in contact with carbonaceous material, tube in e orm of a coil, means for introducing solid carbonaceous contents, so that the steam and carb material react substantially instantaneously to orm water gas.

9. In a device for superheating ,steam in contact with solid car such und said tube, said tube being nular chamber through tents rial into'said tube under pressure and tube to heat the saine the passed countercurrent to the flow of the conof the superheater, said straight inlet and outlet extensions of the coil passing directly out of the hot gas chamber.

11. In a device for superheating steam in contact with solid carbonaceous material, a large radius tube in the form of a coil, means for introducing 'steam and finely divide solid carbonaceous material into said tube under pressure and means to heat said tube, said tube beingllocated in an annular Vchamber through which hot ases are passey countercurrent to the-flow o the contents of the superheater, and said `annular chamber decreases in area inthe direction oi the iiow' of the combustion gases.

12. In a device Jfor superheating steam in contact-With solid carbonaceous material, a large radius tube in the orm o a coil wit straight tangentially disposed inlet and outlet extensions, means for introducing steam and finelyfdivided solid carbonaceous matemeans to heat said tube progressively to higher temperatures from inlet to outlet of tube, said tube being provided with a. twisted alloy metal ribbon along the inside of the same, an with its tangential extensions passing directly out of said heating means.

13. In a device for superheating steam in contact with solid carbonaceous material, a tube, means comprising a steam jacketed feederA for introducing steam and iinely divided solid carbonaceous material into said tube under pressure and means to heat said tube. 14. In a device or .superheating steam contact with solid carbonaceous material, tube` means for introducing steam and e divided solid carbonaceous material into said tube under p ressure, means to heat said tube,

and a heated bin for supplying carbonaceous variable rates to said {irst named mate 'al at means. 15. In a device for superheating steam in contact with solid carbonaceous material, a large radius coiled tube, means for introdu d inely divided solid carbonaceous material into said tube under pressure and means to pass electricity through sai a plication of heat being such that the velocity of the materi in they coil is increa in the direction o the outlet.

16. The process of superheating steam at high temperatures in contact wit carbonaceous materialywhich comprises introducing the carbonaceous materials in iinely divided foi-m into a feeding .and preheating device under pressure to receive treatment therein, agitating the material in the presence of steam produce fluidity and passing said treated material'nto. a stream of steam under pressure into a tube superheater, the superheating heater from the outside to high temperature d stantially solid particles to move in vand causing the with the inside walls of continuous contact the tube. v

17. The process of generating and supersteam in cont-act with solid carbonacomprises mixing soli carbonaceous materials in finely divided form d together with steam'and water under pressure her at high velocity while applying sufficient heat to effect superheat of the steam, and effecting the subinstantaneous formation of water Liivvis onanieren.

gas.

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